One such light conductor coupling is for example known from DE 28 54 962 C2, in which an intermediate buffer coupling for rail vehicles is described. A cable coupling belongs to the intermediate buffer coupling which among other things serves to transmit impulses for the control of the braking and driving currents from one vehicle to the other in a train of vehicles. The cable coupling consists of two contact carriers each of which is carried by a respective one of the vehicles and in which along with a plurality of electrical contacts a light conductor is as well arranged. Of the two light conductors at least one is elastically biased so that the two light conductors are pressed against one another with their end faces when the contact carriers upon the coupling of the vehicles are moved against one another. Through these pressed together light conductors optical signals can be transmitted from one vehicle to the other.
From DE 198 07 596 C2 a light conducting plug connector of the previously mentioned type is known in which not only one, but both light conductor elements are elastically biased.
When light conductor couplings of the above-mentioned type are used under rough conditions, such as for example for the transmission of signals between coupled vehicles, there however appear many transmission failures. A reason for this lies in that the optical signals are heavily attenuated in their transmission from one light conductor element to the other, both because of a dislocating movement as well as because of a tilting of the optical axes of the two light conductors relative to one another, which leads to a falsification of the optical signals. One such dislocating movement or such a tipping of the optical axes of the light conducting elements can however hardly be avoided in the case of vehicles which are coupled with one another, since the two coupling parts are not rigidly connected with one another and are relatively heavily mechanically stressed. Further reasons for an unreliable signal transmission lie in the sensitivity of such light conductor couplings to abrasion and contamination which in relatively rough conditions are likewise unavoidable.
To circumvent these problems an optical signal coupling is proposed in DE 29 22 937 C2 in which the light conductors are not pushed together at their end surfaces, and instead the light is transmitted with the help of lens pieces through the air from one light conductor to the other. Such a signal coupling is however relatively complicated and expensive and cannot offer the reliability which was expected of it.
In consideration of the above mentioned difficulties in DE100 52 020 A1 it has been proposed, in the case of applications under rough conditions, to do away entirely with a customary optical coupling of light conductors and instead of this to first convert the optical signals conducted in a first light conductor into electrical signals, to transmit these signals over customary electric couplings, to again convert the electrical signals into optical signals and to feed those optical signals into a second light conductor. With this solution, one loses above all the previously mentioned advantages of a light conductor coupling, namely the increased transmission bandwidth and a lower susceptibility to electromagnetic disturbing fields, especially those which always appear if in the immediate vicinity high currents are also transmitted, as for example in cable couplings for rail vehicles is often the case.
The invention has as its basic object the provision of a light conductor coupling which is of simple construction and which permits a disturbance insensitive signal transmission.